During this fellowship period I propose studies of the oxytocin-binding protein neurophysin from the pig to address questions about protein folding mechanisms, self-association and targeting. Earlier work on neurophysin properties have focused on bovine neurophysins. Up to now porcine oxytocin-associated neurophysin has not been studied in detail. We have preliminary NMR evidence that this porcine neurophysin forms a dimer at much lower concentrations than bovine neurophysin and that it is a much more stable protein. Of special interest is evidence from recent studies which shows that porcine oxytocin-associated neurophysin is able to fold in the absence of hormone, which makes it an attractive candidate for cloning and gene expression. The more stable porcine and self-folding neurophysin provides the opportunity to address questions about protein interactions which the bovine neurophysin is not well suited to answer. These studies should also provide insights into the mechanisms by which neurosecretory proteins are processed and sorted.